With the number of older adults expected to double and the proportion of people 65 and older expected to rise to 22% by 2020, it is critical to develop and test population-based approaches for large scale, effective health promotion for our aging society. This will permit evidence-based decisions as to how to deploy resources in order to have optimal impact on the health of older adults. This Administrative Core supports the operations and overall coordination of a program project dedicated to contributing to this goal by conducting a randomized, controlled trial of the Experience Corps program and its cost-effectiveness and cost-benefit impact locally and societally. This program is a senior volunteer program which places people 60 and older in meaningful roles in public elementary schools, roles designed to have high impact on children's' outcomes; the program attracts and retains older adults, 15 hours per week, for its opportunity to give back. However, designed into the program is a health promotion program, intending to increase social, cognitive and physical activity. This application will, in a University-community-city collaboration, conduct a rigorous evaluation of the impact of the scaled-up program through a randomized controlled evaluation: of older volunteers to determine whether Experience Corps prevents or slows physical disability, falls and cognitive decline (Project 1); of schools, to determine if children improve academically, behaviorally and in readiness to learn as a result of the social capital offered by Experience Corps and, hence, our aging society (Project 2); of the potential mechanisms of program action on brain structure and executive function (Project 3); of program effects on social and psychological mechanisms and outcomes (Project 4); and, finally, we will conduct a cost-benefit analysis of the program, taking impact on both older adults and children into account. The work of the 5 projects and 3 supporting cores will be mutually interconnected and synergistic, and will be interdigitated through a Steering Committee and an Executive Committee operated within this Administrative Core (Core A). This Core will project coordination and interdigitation, overall organization and budget management for all Projects and cores, monitor progress and effectiveness, produce reports, organize DSMB meetings, and coordinate community relations. Overall, this program project is designed to evaluate the utility and effectiveness of Experience Corps as a social model for health promotion for an aging society.